Jump to main content
Jump to site search
PLANNED MAINTENANCE Close the message box

Scheduled maintenance work on Wednesday 27th March 2019 from 11:00 AM to 1:00 PM (GMT).

During this time our website performance may be temporarily affected. We apologise for any inconvenience this might cause and thank you for your patience.

Issue 44, 2018
Previous Article Next Article

Mechanics and nanovoid nucleation dynamics: effects of polar functionality in glassy polymer networks

Author affiliations


We use molecular simulations and experiments to rationalize the properties of a class of networks based on dicyclopentadiene (DCPD), a polymer with excellent fracture toughness and a high glass transition temperature (Tg), copolymerized with 5-norbornene-2-methanol (NBOH). DCPD is a highly non-polar hydrocarbon, while NBOH contains a hydroxy group, introducing polar functionality and hydrogen bonds (H-bonds). NBOH thus represents a possible route to improve the chemical compatibility of DCPD-based networks with less-hydrophobic materials. We systematically vary the NBOH content (polar chemistry) in DCPD networks, while keeping other network parameters nearly constant, including the molecular weight between cross-links, chain rigidity, and Tg. Using molecular dynamics (MD) simulations, we quantify the thermovolumetric and mechanical properties, including Tg, cohesive energy density, stiffness, and yield strength. We compare these results with experiments on networks of similar composition, finding good agreement. The relation between these properties and polar chemistry are studied by examining a secondary network of physical cross-links, formed by hydrogen bonds between NBOH units. Further, we examine nanovoid formation, an energy dissipation mechanism hypothesized to contribute to the toughness of pDCPD. Using metadynamics to accelerate sampling, we quantify the nanovoid nucleation rate under hydrostatic tension, similar to the stress state in the plastic zone preceding a crack tip. Small additions of NBOH have minimal effect, but the rate drops steeply with larger amounts. Several properties are mapped at nanometer scales, including stiffness and mobility, and associated with void nucleation. Estimates of the length- and time-scale of the plastic zone near a crack tip are used in discussing nanovoid formation as a plausible toughening mechanism in these materials. Overall, the results suggest that pDCPD tolerates the addition of some polar chemistry without degrading its excellent mechanical properties.

Graphical abstract: Mechanics and nanovoid nucleation dynamics: effects of polar functionality in glassy polymer networks

Back to tab navigation

Publication details

The article was received on 20 Jul 2018, accepted on 01 Sep 2018 and first published on 05 Sep 2018

Article type: Paper
DOI: 10.1039/C8SM01483C
Citation: Soft Matter, 2018,14, 8895-8911

  •   Request permissions

    Mechanics and nanovoid nucleation dynamics: effects of polar functionality in glassy polymer networks

    R. M. Elder, T. R. Long, E. D. Bain, J. L. Lenhart and T. W. Sirk, Soft Matter, 2018, 14, 8895
    DOI: 10.1039/C8SM01483C

Search articles by author